In the known waste compressors the waste is compressed by means of compressed air. The compressed waste is subjected to a constant state of compression, and this pressure is maintained, even when the waste becomes exposed to further compression. In 80-90% of the compression cycles required for the compression of a bale, when the piston is in its bottom position, before the resistance of the compressed waste exerts a counter pressure corresponding to the pressure, which the piston can exert at an air pressure of 8 bars. When the piston is in its bottom position the compressor continues to work, until the pressure in the cylinder is 8 bars, at which the compressor stops. The pressure in the cylinder remains at 8 bars, until a new portion o waste is to be compressed. When a filling door opens, a fast air-escape valve opens, which causes the compression cylinder to be emptied of air, and the piston—which is spring-loaded—moves upwards to its top position, whereby a pressing plate coupled to the piston also moves upwards and thereby makes room for a new portion of waste on top of the already compressed material. Consequently, the known waste compressors are very energy consuming.
It is a purpose of the invention to describe a partial control system by means of which the consumption of energy can be considerably reduced.
This is achieved by the control system described herein. This arrangement stops the air supply to the compressor, when the piston is in its bottom position.
The compressor according to the invention operates from 1 to a maximum of 8 bars in the cycles, where the bottom position of the piston is reached, before the quantity of waste is sufficiently compressed to be able to exert a counter force corresponding to the compression power of the cylinder.
The noise level will be reduced, because it is proportional to the air pressure and the volume of air.
Because the air consumption is lower, it is possible that the compressor can work faster, and it is possible to employ a compressor with a lower capacity. This also means lower maintenance costs and a longer life of the compressor.